Dual speed paper advance system with skip to format heading

ABSTRACT

A mechanism for controllably advancing web material of indeterminate length, such as paper from a roll, according to a predetermined format and at different speeds. The format information is carried by an endless tape which is normally driven in synchronism with the web and which controls electromagnetic drive clutches and a brake through electronic circuitry. The operation of the brake and clutches controls the distance that the web travels from the generation of a stop signal until the web is actually stopped, and also regulates the longitudinal force on the paper, by controlling the acceleration and deceleration, to prevent tearing when the web is started, stopped, or when the speed of the web is changed. The format tape may be advanced to the format heading independently of the web drive by clutch means for disengaging the format tape from the synchronous drive and by engaging a small motor for independently driving the tape. The tape stops at its format heading automatically as a result of a control signal developed from the tape itself.

United States Patent [72] Inventors John W. Funk Dearhorn; Dean P.Scott, Livonia; James S. McCoy, Detroit, all ot, Mich. [21 Appl. No.784,685 [22] Filed Dec. 18, 1968 [45] Patented Aug. 24, 1971 [73]Assignee Burroughs Corporation Detroit, Mich.

[ 5 4] DUAL SPEED PAPER ADVANCE SYSTEM WITH SKIP T0 FORMAT READING l6Claims,4 Drawing Figs.

.05. CL 226/9, 197/20 [51] Int. Cl. B65h 25/00 [50] Field of Search226/9, 46, 47; 197/20; 83/71 [56] References Cited UNITED STATES PATENTS2,747,717 5/1956 Cunningham et al 226/9 X 2,894,614 7/1959 Lambert etal. 197/20 3,498,514 3 1970 Howardetal.

ABSTRACT: A mechanism for controllably advancing web material ofindeterminate length, such as paper from a roll, according to apredetermined format and at different speeds. The format information iscarried 'by an endless tape which is normally driven in synchronism withthe web and which controls electromagnetic drive clutches and a brakethrough electronic circuitry. The operation of the brake and clutchescontrols the distance that the web travels from the generation of a stopsignal until the web is actually stopped, and also regulates thelongitudinal force on the paper, by controlling the acceleration anddeceleration, to prevent tearing when the web is started, stopped, orwhen the speed of the web is changed.

The format tape may be advanced to the format heading independently ofthe web drive by clutch means for disengaging the format tape from thesynchronous drive and by engaging a small motor for independentlydriving the tape. The tape stops at its format heading automatically asa result of a control signal developed from the tape itself.

PATENTED AUB24|97| SHEET 1 BF 2 INVENTORS.

AGENT JOHN W. FUNK y DEAN P SCOTT JAMESQ S. MCCOY DUAL SPEED PAPERADVANCE SYSTEM WITH SKIP TO FORMAT READING BACKGROUND OF THE INVENTIONThis invention relates to an improved mechanism for highspeed,intermittent movement of web material of indeterrninate length through amachine performing operations upon the web material under control of aformat on an endless tape. In addition to web material our inventionfurther relates to the intermittent movement of sheets of paper of apredetermined length and to continuous forms. Such continuous forms,which may be of multiple thickness, are usually folded in a flat stackrather than being on a roll. Within the context of our invention,therefore, the words web, sheet, paper and form will often be usedinterchangeably and should be so construed except when an ambiguity iscaused by such a construction.

Operations on flexible sheet material may take several forms. It may bedesired, for example, to cut or punch the material or to print on thematerial. Usually, these operations are performed on the web material bymoving it relative to work station. The mechanism of this invention hasits greatest known utility in format tape-controlled machines forhighspeed printing of information from data-processing equipment. Arepresentative machine is that illustrated and described in the U.S.Pat. to Cunningham et al., No. 2,747,717, The format control tapegenerally contains information in the form of a pattern of holes ormarks. This information may be read from the tape in one of a number ofwellknown ways for controlling electromagnetic clutches and brakesthrough standard electronic circuits to result in the desiredintermittent advance of paper.

When a particular sequence of operations is to be performed repeatedly,for example'on continuous forms, it is often desired that each sequencestart at the beginning of a new page. Here the term page refers to apredetermined length of the form, usually between two successive folds.If the sequence of operations does not require that the last page beused completely a long skip, to the start of the next page," may berequired. Furthermore, it is often necessary to skip to the start orheading of the sequence of operations on the format tape such as wheninstalling a new format tape, when installing a new supply of paper, orwhen the paper and format tape become misaligned.

When the format tape and paper are out of alignment present machinesrequire that the operator manually move the paper relative to the formattape since the paper drive tractors and the format tape are coupled forsynchronous motion. For example, when a new format tape is installed itis usually necessary to advance the tape to the format heading. However,if paper is left in the drive tractors while the format tape isinstalled, with the advance of the format tape to its heading, by virtueof the synchronous coupling, there is a corresponding advance of thepaper. Then if the paper is not at the start of a page, the operatormust remove the paper and reinsert it in a position ready to receive thefirst operation from the format tape. During this time the dataprocessor, whose output is the information being printed, must remaininoperative. For more efficient utilization of the data processingequipment a more rapid means for alignment is desired.

Recent advances in the field of high-speed electronic dataprocessingmachines have demanded that the speed of printers be increased in orderto handle the high rate of data flow from such machines. Improvementshave been made in the printing members, advancing from print hammerscarrying the individual characters to rotating printing drums, resultingin less time necessary to print a line of data obtained from thedataprocessing machine. There have also been advancesin rapidly movingthe paper from line to line. The rate of paper movement becomesincreasingly important when it is desired that the information from thedata processor be printed according to a predetermined format sincerelatively long skips between lines of printing may be necessary. Aparticular format may be desired, forinstance, when the printing is tobe placed on a bill, check, ledger sheet or other form.

When long skips are desired, however, it is time consuming and noteconomical to advance the paper at the printing speed since more rapidpaper advance is manageableby present technology. Rapid paper advancewithout printing is referred to as slewing; however, the use of slewingat a speed greater than the printing speed creates several problems. Thefirst problem is that the acceleration and deceleration forces createdwhen changing speeds result in an excessive torque or longitudinaltearing force on the moving paper. A second problem is the overrun ofthe system. Overrun is defined as the distance the paper travels betweenthe generation of a command (e.g., a stop signal) and the completion ofthe command (i.e., the paper being at a standstill). Compensation foroverrun when only one paper advance speed is used is not a difficultproblem but compensation for or the elimination of a different amount ofoverrun, when more than one paper advance speed is used, has not beenaccomplished satisfactorily prior to the method and apparatus which isdescribed in more detail hereinafter.

SUMMARY In a high-speed printer controlled for intermittent printingaccording to a format, for example, on continuous forms, this inventionprovides the improvements of a normal speed paper advance between linesof printing, a higher speed paper advance when more than a predeterminedminimum number of lines is skipped between lines of printing,compensation for normal overrun, elimination of a different amount ofoverrun when the higher speed advance is used, and constant torque whenaccelerating or decelerating, all under synchronized format control.This invention further provides the improvement of independent movementof the format tape to its heading position, and termination of theindependent movement and reengagement of the synchronism under thecontrol of the information on the format tape itself. i

It is accordingly an object of the present invention to provide anew andimproved paper drive system and associated logic circuitry for use indata-processing systems.

Another object of the present invention is to provide an improved systemfor automatically advancing the paper in a high speed printer accordingto, and in synchronism with, a predetermined format; the format, forexample, being carried on a tape.

It is another object of our invention to provide a plurality of clutchmeans, each operable to advance a web at a different speed, undercontrol of the format.

It is a further object of our invention to provide for advance of aformat tape to its heading position independently of the paper advance;and for the return to synchronized tape and web advance automaticallybased on the information carried on the tape itself.

Yet another object of the present invention is the operation of a paperdrive system under control of a format tape to decrease the amount ofacceleration and deceleration torque On the paper when the paper speedis changed, when the paper is started, and when the paper is stopped, toprevent tearing of the paper.

A still further object is to provide paper drive apparatus under controlof a format tape which will compensate for normal overrun and eliminatethe difference in overrun which would otherwise occur in multispeedpaper advance systems.

The foregoing objects and features of novelty which characterize ourinvention, as well as other objects of the invention, are pointed outwith particularity in the claims which form a part of the presentspecification.

For a better understanding of our invention, its advantages and thespecific objects attained with its use, reference should be had to theaccompanying drawings and descriptive matter.

BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiment and alternateembodiments for intermittently advancing sheet material are illustrated,in which like numerals refer to the same element and in which:

FIG. 1 shows a schematic diagram of a system operable in accordance withthe objects and features of our invention, including intermittentlyadvancing the sheet material and independently advancing the formattape;

FIG. 2 illustrates a schematic diagram of a portion of one improvementdirected to the independent advancement of the format tape;

FIG. 3 is a partial schematic of the logic circuitry of FIG. 1 modifiedto form an alternate embodiment according to the principles of ourinvention; and

FIG. 4 is a partial schematic of the logic circuitry of FIG. 1 modifiedto permit parallel operation of the high-speed and low-speed clutches.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows generally theelements of a paper drive apparatus for a high-speed printer associatedwith dataprocessing equipment. Upper and lower tractors or other paperdrive means 55, which contact the web of paper 51 and cause it toadvance, are themselves driven by a drive shaft 11 through worm gearsand shafts 53. Constantly running electric motor 17 is operablyconnected to the drive shaft 11 through electromagnetic clutches 13 and15. Electromagnetic brake l9 acting on shaft 11 through a worm gear andelectromagnetic clutches l3 and may be of any known type that respondrapidly when a voltage is impressed to their individual electromagneticcoils. An example of a clutch where two clutch plates are drawn togetherin rapid response to an electromagnetic field is shown in the aforesaidUS. Pat. No. 2,746,717 to .l. M. Cunningham et al.

Clutch 13 operates drive shaft 11 at low speed and clutch 15 operatesdrive shaft 11 at high speed. The low-speed clutch is energized to itsengaging position when the paper is to be advanced'one or more lines.For normal printing and paper advance a drive speed such that the paperwill advance at approximately 25 inches per second has been foundsatisfactory. It has also been found that there is no tearing of paperwhen the paper is accelerated from a stop to this low speed by a tractordevice having pins which engage holes along the papers edge. The problemof tearing the paper is created by the change in longitudinal stresswhich is a function of the acceleration of the paper either from astopped position to a particular paper speed, or the acceleration ordeceleration when changing from one paper speed to another paper speed,or the deceleration when stopping the paper.

If a slew of several lines is required, it is more economical to advancethe paper at a higher speed, for example, 75 inches per second. This maybe accomplished either by first engaging the low-speed clutch,disengaging the low-speed clutch when the low speed is reached, and thenengaging the high-speed clutch (sequential clutch operation) or byengaging both clutches and then disengaging the low-speed clutch whenthe paper speed reaches 25 inches per second (parallel clutchoperation). Of course the high-speed clutch alone could be used, butthis causes a greater acceleration which is manifested by a greatertearing force on the paper.

When it is desired to stop the paper which is traveling at the highspeed, the paper speed is first reduced to the lower speed bydisengaging the high-speed clutch and then engaging the low-speedclutch. After the paper stabilizes at the lower speed the low-speedclutch is disengaged and the brake is engaged. The primary reason forthis step down in speed is to reduce the deceleration forces which arecreated by the braking system and therefore prevent the paper fromtearing. This tearing would normally occur as a result of thedeceleration forces if the paper were brought from a high speed to arapid stop. The force caused by the braking system is directlyproportional to the countertorque supplied by the brake relative to thetotal equivalent rotational inertia of the system. When the brake isused in the disclosed inventive fashion it is energized to supply itsmaximum torque so that the deceleration forces on the paper would beessentially the same regardless of the paper speed. This means thatthere is no different longitudinal stress on the paper when it isstopped from high speed qr when it is stopped from low speed. Whetherthe deceleration is high or low the force on the paper would be thesame.

The second problem which is solved by maintaining a constantdeceleration torque is controlling the distance that the paper movesafter the brake has been applied. This distance is roughly proportionalto the square of the paper speed. Since .the distance the paper travelsafter the brake is applied is considerable, (at a low paper speed of 25inches per second it is in the neighborhood 0.050 inches), it is veryimportant to account for overrun in determining the ultimate position ofthe paper after a stop signal is applied. In order to account for this alead time is used for the brake. Therefore, when printing at a verticalspacing of 6 lines per inch or 8 lines per inch, for example, stopsignals must be delivered at the appropriate time to insure that the 6-or 8 -line per inch vertical spacing will be held constant, and thatthere will be no vertical spacing errors due to the overrun of thesystem after the brake is applied. It is very important to keep thevertical spacing constant and to prevent the printed lines from driftingout of position relative to the lines of continuous printing, especiallywhen printing on a prepared form. Because static friction is generallymuch greater than dynamic friction, the brake torque tends to be amaximum when the relative motion between the friction surfaces of thebrake ceases. Therefore, by regulating the distance the paper movesafter the brake is applied, it is possible to prevent verticalmisalignment of the printed lines. I

In order to compensate for overrun it is necessary to apply the brakesignal when the paper is sufficiently ahead of the desired stoppingposition such that the overrun will bring the paper exactly to thedesired position when the paper motion has ceased. The period of timerequired for lowering the paper advance from high speed to low speed iscompensated for by the positioning of the coded control signals on theformat tape. This is called the lead time of the brake signal and may bederived experimentally by measuring the paper travel after the brake isapplied. Applicants have discovered that the compensation for overrun ata single speed is sufficient in their novel multispeed paper advancesystem since the overrun associated with the other speeds is effectivelyeliminated by the same general procedure as the solution to the problemof excessive torque tearing the paper. Specifically, by firstdecelerating the paper to the low speed (by disengaging the high-speeddrive and engaging the low-speed drive for a suitable time) and thenstopping the paper. This allows the paper to stabilize at the low speedbefore the brake signal is sensed from the format tape. Therefore, theonly overrun which must be compensated for by a lead time is that causedby braking from low speed.

It should be noted that this invention could be extended to more thentwo paper speeds, that is, regardless of how many different paper speedsmay be used, by always decoupling all paper drives except the low-speeddrive, and by always advancing the paper for a suitable time at the lowspeed, to stabilize the paper motion at low speed, it will always bepossible to eliminate the overrun associated with different paper speedsand compensate for the overrun associated with low speed when brakingthe paper to a stop.

To control the speed at which the paper advances and control the pointat which it stops to receive a new line of printing, a format tape 23 isutilized. Control drive shaft 21, which advances tape 23, is normallydriven by shaft 11. The coded information on the format tape may be readby a conventional tape reader 27 which emits a pulse each time aperforation 49 (FIG. 2) is sensed. The output pulse keys the electroniccircuitry which in turn controls the brake and clutches to effect thedesired change in the paper advance. The conventional tape reader couldhave a photoelectric cell for each channel of the tape, althoughmagnetic, optical, or wire brush sensing would be equally feasible. Abrush system for reading a format control tape is described in U.S. Pat.3,094,261 to T. W. Thompson.

The format tape code can be one of a variety of codes known in the art.Shown in FIG. 1, for example, is a four channel tape, one channel foreach change of paper advance which the control mechanism may be calledupon to perform. For instance, the left-hand channel could have aperforation at that point in the format where the paper should beshifted from a low-speed advance to a high-speed advance. Likewise, asecond channel could be utilized to control the point at which the paperwould shift from a high-speed to a low-speed advance. A third channelcould be used to operate the brake and deenergize the clutches. A fourthchannel would be necessary in connection with the format tape advancefeature to be described hereinafter. Additional channels or multiplesignals coupled with a change in the logic circuitry may be utilizedboth for a two speed printer and for a printer which operates at morethan two speeds.

The format tape 23 is normally designed to provide a repetitive set ofcontrol signals, and for this purpose a continuous or endless tape isusually preferred as illustrated in the drawing. The length of theformat tape is usually the length of the format desired to be printedout on the moving paper. Since various operations may demand differentformat lengths, the format tape roller 37 is made adjustable in distancefrom the drive roller by having shaft 39 of roller 37'adjustablerelativeto the machine frame.

Control shaft 21 has two clutches 29 and 31 disposed between its directconnections to shaft 11 and to format tape drive roller 25. Clutch 29 isa positive gripping type which is manually operated to allow theoperator to adjust the relative positions of the paper 51 and the formattape 23 whenever necessary as is well known in the art. Althoughcommercial clutches are satisfactory, Applicants have designed a pinclutch 29 having 24 pins and 25 holes. Once the paper is manuallyadjusted there is little or no relative movement is engaged since theinertia that a continuous connection would add to the rest of the systemwould slow down the response to changes in paper advance speed. Theformat tape motor clutch arrangement of FIG. 2, however, adds littleinertia to the system since disk 47 can be of light weight.

Solenoid 41 has its plunger connected to the motor 35 so that the motormay be rocked about pivot 57, approximately at the motors center, intoengagement with drive shaft 21 against the yielding resistance ofresilient means such as spring 43. When the format tape has reached itsheading, the tape reader will sense this, by a particular code of theperforations, and produce a signal which will cause solenoid 41 to bedeenergized, motor 35 to be deenergized and clutch 31 to be energizedagain so as to create a positive connection between the format tape anddrive shaft 11 through format drive shaft 21. The system is then readyto begin a new format-printing cycle. I

The electronic circuitry used to convert the pulses from the fourchannels of tape reader 27 into control of the clutches and brake may beany suitable switching circuit. FIG. 1 shows an example of a circuitthat may be utilized. Flip-flop elements 61, 63, 65 and 67 function asbasic switching elements. F ollowing customary nomenclature, when apulse is presented at the S input terminal the flip-flop will beswitched so that a constant voltage appears at the output marked 1 and avery low or zero voltage condition will exist at the output 0. When apulse is presented at the R input to one of these flipflops its 0 outputwill be a steady high voltage while its 1 output will be near zerovolts. Flip-flop 63 (FF2) controls the power switch 71 forelectromagnetic brake l9. Flip-flop 61 (FFl) controls power switch 69which operates format disengage clutch 31, format drive motor engageclutch 33 and the format tape motor 35. Flip-flop 65 (FF3), throughpower switch 73, operates the low-speed clutch l3. Flip-flop 67 (FF4)operates high-speed clutch 15 through power switch 75.

To explain the operation of the mechanism in light of its controllingelectronic circuit, consider only FF2 to be in its 1 state (the otherflip-flops being in the 0 state) thus energizing brake 19 and presentinga constant voltage to one between the format tape and the paper to causemisalignment since whenever the pin clutch is reengaged a pin willalmost immediately drop into a hole.

Format tape disengage clutch 31 is electromagnetically operated forreleasing the positive connection between the drive shaft 11 and formattape drive so that the format tape may be operated independently of thepaper 51 being printed upon. Similar to clutch 29, clutch 31 also mustbe of the positive engagement type so the relative alignment between theprinted paper and the format tape will remain constant. Here a dogclutch is preferable with the engagement of the dogs (attached to onerotating member) and the teeth (on the other rotating member) beingcontrolled electromagnetically.

Connected to control shaft 21, such as to its left end as viewed in FIG.1, through clutch 33 is a source of motive power for driving the shaftindependently of the paper ad vance shaft 11. In this instance, thispower source is shown as a separate motor 35. When it is desired thatthe format tape be advanced independently of the drive shaft 11, such asto its format heading, electrical energy is applied to clutch 31 torelease it and then energy is applied to motor 35 and to clutch 33.

FIG. 2 shows a preferred form of the apparatus for independentlyadvancing the format tape 23. As solenoid 41 operates to rotate motor 35about a pivot 57, motor shaft 45 (attached to the frame of motor 35)moves into engagement with disk or plate 47. This comprises the clutch33 of FIG. 1. Plate 47, attached to drive shaft 21, is preferably coatedwith a soft plastic material so that the motor shaft 45 can frictionallyengage plate 47 without the need for extreme precision in alignmentbetween these two parts. The format tape drive motor 35 is not connectedto shaft 21 except through the frictional interconnection between theshaft 45 and plate 47 when the clutch input of AND gate 77. Thisprovides an electrical interlock since this input to AND gate 77 ispresented only when brake 19 is energized. Therefore FFl cannot be set,and the skip to heading feature cannot be employed, except when brake 19is energized, i.e,, skip to heading can only occur when the paper isstopped. FF 1 may be changed from its 0 state to its 1? state bymomentarily connecting voltage source 87 to the other input of AND gate77 through a manual pushbutton switch 85. This will cause clutch 31 tobe deenergized, and clutch 33 and motor 35 to be energized which willresult in the format tape advancing independently of the paper whichremains stopped by brake 19. When the format tape has advanced to itsheading position the tape reader will emit a pulse through line 89 whichwill reset FF 1 and thus energize clutch 31, deenergize clutch 33 andturnoff motor 35. The format tape will then be at its heading positionready to receive printing data from the external data-processing unit.Without this disengageable format tape advance feature the operatorwould have the time consuming task of manually aligning the format tapeand the paper.

After a line of printing is completed, a pulse will be received atterminal 83 from the data processor. This pulse will reset FF2, thusreleasing brake 19, set FF3 by the pulse applied through OR gate 81 andenergize low-speed clutch 13. The paper 51 will then be started andadvanced at slow speed until some other signal triggers the electroniccircuit.

When a pulse is emitted on line from tape reader 27 as a result of ahole in the proper channel of the format tape 23, FF3 will be reset bythe pulse applied through OR gate 97 and FF4 will be set. This resultsin the low-speed clutch 13 being turned off and the high speed clutch 15being turned on. The paper is now advancing at the higher rate of speed,for example, 75 inches per second. It has been found most economical touse the high-speed advance whenever the distance between successivelines of print exceeds 1 7/16 inches. At a vertical spacing of eightlines per inch, for example, the high-speed advance would be used anytime twelve or more lines are to be skipped. When a pulse is created online 93, FF3 will be set through OR gate 81 and FF4 will be reset. Thisresults in highspeed clutch 15 being turned off and the low-speed clutch13 being turned on. When a stop signal is sensed by the tape reader apulse will be created on line 91 which will set FF2 by applying a pulseto AND gate 79 and reset FF3 through OR gate 97, thus applying brake 19and removing energy from clutch 13. Note that FF2 cannot operate toenergize brake 19 unless FF4 is in its state, because the 0 output fromFF4 is one input to AND gate 79, and AND gate 79 is the input to the Sterminal of FF2. This is an electrical interlock which prevents thepaper from being stopped while traveling at high speed. The paper may bestopped only while traveling at the low speed.

DESCRIPTION OF THE ALTERNATE EMBODIMENTS In order to provide higheracceleration and the extremely rapid response of the drive clutches andbrake which are essential for high-speed computer operations,alternative embodiments to the electronic circuitry discussed above maybe employed with our invention. The circuitry shown in FIG. 3 willperform the desired functions and also provide higher acceleration anddeceleration. The particular logic circuitry shown would take the placeof the logic circuitry shown within the dotted block 59 of FIG. I. Inthe alternate embodiment of FIG. 3 means are provided for delivering arelatively short duration high-voltage pulse to the brake or clutchesand, in response to this pulse, the brake or clutches provide a higherthan normal acceleration or deceleration. At the termination of thehigh-voltage pulse, means are provided to continue the operation of therespective brake or clutch in its normal operating condition to eithermaintain speed (when the clutch is engaged) or to maintain the paper ata stop (when the brake is engaged). I

The operation of FF2, FF3 and FF4 is the same as described in thepreferred embodiment. However, instead of the 1" output of eachflip-flop activating a power switch, the flip-flop output activateshighand low-level drivers as will be hereinafter described. Followingthe same terminology as used in the explanation of FIG. I, consider onlyFF2 to be in the 1 state by virtue of a pulse being passed through ANDgate 79 to the 8" terminal of FF2 as described with reference to FIG. I.The output of FF2 is a constant level pulse which triggers one-shotmultivibrator 101 and also sets flip-flop 103 (FF). FFS controls theoperation of low-level driver 121, which has an output level of about 10volts, and the one-shot 101 controls the high-level driver 119 which hasan output in the neighborhood of 50 volts. Each of these drivers may beconventional power transistors. The output from high-level driver 119,together with the output from low-level driver 12], will far exceed thecontinuous voltage rating of the brake. They may be used togetherwithout damaging the brake only because of the short duration of thehigh-level signal controlled by the multivibrator. This large signalserves to reduce the electrical time delay of the brake which is causedby inductive reactance. In addition this signal provides a momentarycurrent level in the brake far exceeding the continuous rating of thebrake to provide an unusually high torque which, in turn, will providethe highest possible deceleration that the brake can produce. During theinitiation of the braking the highand low-level drivers provide thepulse to start the braking operation which decelerates the moving paper.The time duration of this pulse is set to coincide with the length oftime required to stop the paper from its lower speed of inches persecond. As the paper stops the duration of the high-voltage pulse endsand the output from the low-level driver alone operates to hold thepaper in its stopped position. The lowlevel driver supplies enoughvoltage to hold the brake energized and yet it is a voltage low enoughthat it may be continuously applied without damaging the brake. In FIG.3 the power supply and ground, shown by way of illustration as connectedonly to high-level driver 119, should be understood, however, to beconnected to each of the high-level drivers and low-level drivers.

When the format tape has advanced to its heading position as describedwith reference to FIG. 2, one channel of the tape reader will emit apulse through line 89 which will reset FFl, engage clutch 31, disengageclutch 33, and turn off motor 35. After a line of printing is completeda new pulse will be received at terminal 83 shown in FIG. 1. This pulsewill reset F F2 which provides a 0 output which is, in turn, supplied tothe R" terminal of FF5 thereby releasing the brake 19 by discontinuingthe input to the low-level driver 12]. As seen in the logic circuitry ofFIG. 1 the pulse which resets FF2 also sets FF3 through OR gate 81. Theoutput of FF3 in the embodiment of FIG. 3 goes to a one-shotmultivibrator and to the S terminal of flipflop 107 (FF6). Similar tothe operation of the brake 19, the high-level driver 123, upon receivinga signal from the multivibrator 105, emits a highvoltage short durationpulse. At the same time low-level driver 125, in response to the 1output of the FF6 emits a lower voltage pulse. As in the description ofthe brake operation, the combination of these pulses drives thelow-speed clutch 13. The combined effect of these voltages exceeds therating of the clutch and must, therefore, be of short duration. One-shot105 delivers a pulse ofa time duration equal to the time necessary forthe paper to reach the low speed. Once the paper has reached its lowspeed the high-level driver 123 is cut off since one-shot 105 hasstopped passing the signal and the lowlevel driver 125 supplies thenecessary power to the low-speed clutch 13 to continuously drive thepaper at its low speed.

Similarly, when a pulse is emitted along line 95 from the tape reader27, FF3 will be reset by a pulse applied through OR gate 97, and FF4will be set. The output from FF4 will energize one-shot multivibrator109 which in turn will energize the high-level driver 127 to provide ashort duration highvoltage pulse to the high-speed clutch 15. The outputof FF4 also sets flip-flop 111 (FF7) which in turn energizes low-leveldriver 129. As in the operation of the other highand low-level drivers,the multivibrator 109 is selected to provide a highlevel pulse for atime duration sufficient to allow high-speed clutch 15 to increase thespeed of the paper to the desired speed. At this point the high-levelsignal from the driver 127 will cease and the low-level driver 129 willcontinue to operate maintaining the high-speed clutch 15 at its steadyspeed, which, for example, would drive the paper-at 75 inches persecond. When a pulse is generated on line 93, FF3 will be set through ORgate 81 and FF4 will be reset. In this fashion the high-speed clutchwill be deenergized and the low-speed clutch will be engaged asdescribed with reference to FIG. 1. When a stop signal is sensed by thetape reader, as described in the embodiment shown in FIG. 1, a pulsewill be created on line 91 which will set FF2 by applying a pulse to ANDgate 79 and reset FF3 through OR gate 97. This will deenergize lowspcedclutch I3 and apply brake 19 in the manner described previously. Againthe AND gate 79 requires its other input from the 0" output of FF4providing the electrical interlock to insure that the brake is notapplied while the high-speed clutch is engaged.

When it is desired to operate the high-speed and low-speed clutches inparallel, thereby providing an even higher acceleration from a stop tothe low speed, the circuitry shown in FIG. 4 will provide this featurewhen it is substituted for the logic circuitry shown within the dottedblock 58 of FIG. 1. The elements of FIG. 4 are the same as those withinthe dotted block 58 with the addition of a lead from minal 83 to aswitch 56 and continuing as a separate input to the S terminal of FF4.The use of the switch is optional and provides greater flexibility aswill be described hereinafter.

When a pulse is received at 83 from the computer indicating the end of aline of print this pulse deenergizes the brake by the computer ter-'applying a pulse to the R terminal of FF2 and energizes the low-speedclutch by applying a pulse to the S terminal of FF3 as in the discussionof FIGS 1 and 3. In addition assume switch 56 to be closed completingthe circuit to the S terminal of FF4. The high-speed clutch will also beenergized providing parallel operation of the high-speed and low-speedclutches. A separate connection is required to the S terminal of FF4 toavoid applying a pulse to the R terminal of FF3.

Care must be taken that the format tape applies a pulse on line 95 bythe time the paper reaches low speed. This pulse on line 95, as in theprior embodiments, resets FF3, and prevents burnout of the low-speedclutch as the paper speed increases above the low speed because thehigh-speed clutch is also energized.

If parallel operation of the clutches (below low speed) is to be used inall instances, switch 56 may be omitted, and the lead from terminal 83would go directly to the S terminal of FF4. By using the switch,however, greater flexibility is achieved since the operator may manuallyclose or open the switch as desired. In some formats it may be desirableto use parallel operation if there are, for example, repeated longskips, none of which exceed the 1 7/16 inches minimum neces' sary forhigh-speed operation.

It should be realized that the modification of FIG. 4 may be used withor without the modification of FIG. 3 and no change in wiring isrequired other than that already explained. Furthermore it should berealized that changes in the logic circuitry of blocks 58 and 59, otherthan that shown in FIG. 4 will be obvious to those skilled in the art sothat, for example, parallel clutch operation may be controlled entirelyby the information on the format tape.

This invention has been described in the environment of a high-speedprinting machine. It is obvious, however, that the format tape advanceand dual-speed advance features may be incorporated in any machinecontrol device for advancing material of fixed or indeterminate length.It is also within the scope of our invention to modify the invention toprovide more than two paper advance speeds, slew speeds, and printingspeeds. Our invention, therefore, should only be limited by the scope ofthe appended claims.

What is claimed is:

1. An apparatus for advancing material through a work area according toinformation on a selected endless format tape, comprising:

means for advancing said material at at least two different speeds;means engaged with said material-advancing means for normally advancingsaid tape in synchronism therewith; and

power system means for disengaging said synchronized tape advancingmeans from said material-advancing means and for independently advancingsaid tape.

2. The apparatus of claim I wherein said power system means includes,

an electrical interlock for preventing concurrent operation of saidindependent tape-advancing means and said material-advancing means, and

an electrical interlock for preventing stopping of saidmaterial-advancing means unless said material is advancing at apredetermined speed.

3. The apparatus of claim I wherein said power system means includes;

logic means responsive to said tape information for disengaging saidindependent tape-advancing means and for reengaging said synchronizedtape-advancing means.

4. The apparatus of claim I wherein said power system means includes;

an electrical interlock for preventing the operation of said independenttape-advancing means during the operation of said material-advancingmeans.

5. The apparatus of claim 1 wherein said material-advancing meansincludes;

drive means for advancing the material at individual ones of said twodifferent speeds;

Ill

means for stopping the advancing of said material; an

logic means responsive to said tape information for selectivelyoperating said drive means.

6. The apparatus of claim 5 wherein said logic means includes;

an electrical interlock for preventing the operation of said stoppingmeans unless said drive means is operating at a predetermined one ofsaid speeds.

7. In an apparatus for advancing material through a machine according toformat information contained on an endless control tape the improvementcomprising;

means for advancing said control tape in synchronism with said materialadvance;

clutch means for disengaging said synchronized tape-advancing means; and

power system means for advancing the control tape independently of saidmaterial advance.

8. The improvement of claim 7 wherein said power system means includes;

logic means responsive to said format information for disengaging saidindependent tape advance, and

said clutch means being responsive to said logic means for reengagingsaid synchronized tape-advancing means.

9. The improvement of claim 8 wherein said logic means ineludes;

an electrical interlock for preventing concurrent operation of saidindependent tape-advancing means and said material advance.

10. The improvement of claim 7 wherein said power system means includes;

a tape drive roller,

a tape drive motor, and

means coupling said tape drive roller and said tape drive motor foradvancing said control tape.

' II. The improvement of claim 10 wherein said coupling means includes;

a disk for rotating said tape drive roller, said disk having a softplastic coating and being disposed for engagement with said tape drivemotor.

12. In an apparatus for advancing material past a work station accordingto format information contained on a control tape, the improvementcomprising:

means for advancing the material at individual ones of two differentspeeds;

means for normally advancing said control tape in synchronism with saidmaterial;

means for stopping the advance of said material and independentlyadvancing said control tape; and

logic means responsive to said control tape for selectively operatingsaid material-advancing means and said stopping means.

13. The apparatus of claim 12 wherein said logic means further includes;

an electrical interlock for preventing the operation of said stoppingmeans except when the material is advancing at a predetermined one ofsaid speeds.

14. The apparatus of claim 13 wherein:

said material-advancing means includes at least two clutches, each ofsaid clutches for advancing said material at a different speed, and

said logic means includes means for permitting simultaneous engagementof at least two of said clutches.

15. In a high-speed printer having paper advance synchronouslycontrolled by an endless tape having a formatheading location, theimprovement comprising:

means for advancing said material at at least two different speeds, aprinting speed and slewing speed,

means responsive to said tape for braking said material advancing means,

electrical logic means for interlocking said braking means operationwhile said material is advancing at said slewing speed; and

aligning means for selectively disengaging synchronous movement of saidtape and material and for automatically and independently advancing saidtape to said formatheading location and reengaging said tape. 16. Theprinter according to claim wherein said aligning

1. An apparatus for advancing material through a work area according toinformation on a selected endless format tape, comprising: means foradvancing said material at at least two different speeds; means engagedwith said material-advancing means for normally advancing said tape insynchronism therewith; and power system means for disengaging saidsynchronized tape advancing means from said material-advancing means andfor independently advancing said tape.
 2. The apparatus of claim 1wherein said power system means includes, an electrical interlock forpreventing concurrent operation of said independent tape-advancing meansand said material-advancing means, and an electrical interlock forpreventing stopping of said material-advancing means unless saidmaterial is advancing at a predetermined speed.
 3. The apparatus ofclaim 1 wherein said power system means includes; logic means responsiveto said tape information for disengaging said independent tape-advancingmeans and for reengaging said synchronized tape-advancing means.
 4. Theapparatus of claim 1 wherein said power system means includes; anelectrical interlock for preventing the operation of said independenttape-advancing means during the operation of said material-advancingmeans.
 5. The apparatus of claim 1 wherein said material-advancing meansincludes; drive means for advancing the material at individual ones ofsaid two different speeds; means for stopping the advancing of saidmaterial; an logic means responsive to said tape information forselectively operating said drive means.
 6. The apparatus of claim 5wherein said logic means includes; an electrical interlock forpreventing the operation of said stopping means unless said drive meansis operating at a predetermined one of said speeds.
 7. In an apparatusfor advancing material through a machine according to format informationcontaiNed on an endless control tape the improvement comprising; meansfor advancing said control tape in synchronism with said materialadvance; clutch means for disengaging said synchronized tape-advancingmeans; and power system means for advancing the control tapeindependently of said material advance.
 8. The improvement of claim 7wherein said power system means includes; logic means responsive to saidformat information for disengaging said independent tape advance, andsaid clutch means being responsive to said logic means for reengagingsaid synchronized tape-advancing means.
 9. The improvement of claim 8wherein said logic means includes; an electrical interlock forpreventing concurrent operation of said independent tape-advancing meansand said material advance.
 10. The improvement of claim 7 wherein saidpower system means includes; a tape drive roller, a tape drive motor,and means coupling said tape drive roller and said tape drive motor foradvancing said control tape.
 11. The improvement of claim 10 whereinsaid coupling means includes; a disk for rotating said tape driveroller, said disk having a soft plastic coating and being disposed forengagement with said tape drive motor.
 12. In an apparatus for advancingmaterial past a work station according to format information containedon a control tape, the improvement comprising: means for advancing thematerial at individual ones of two different speeds; means for normallyadvancing said control tape in synchronism with said material; means forstopping the advance of said material and independently advancing saidcontrol tape; and logic means responsive to said control tape forselectively operating said material-advancing means and said stoppingmeans.
 13. The apparatus of claim 12 wherein said logic means furtherincludes; an electrical interlock for preventing the operation of saidstopping means except when the material is advancing at a predeterminedone of said speeds.
 14. The apparatus of claim 13 wherein: saidmaterial-advancing means includes at least two clutches, each of saidclutches for advancing said material at a different speed, and saidlogic means includes means for permitting simultaneous engagement of atleast two of said clutches.
 15. In a high-speed printer having paperadvance synchronously controlled by an endless tape having aformat-heading location, the improvement comprising: means for advancingsaid material at at least two different speeds, a printing speed andslewing speed, means responsive to said tape for braking said materialadvancing means, electrical logic means for interlocking said brakingmeans operation while said material is advancing at said slewing speed;and aligning means for selectively disengaging synchronous movement ofsaid tape and material and for automatically and independently advancingsaid tape to said format-heading location and reengaging said tape. 16.The printer according to claim 15 wherein said aligning means includes:electrical logic means for interlocking said paper advance during saidindependent tape advance.